kingdom plantae · -absorb water & minerals -anchors the plant 14 . ... absorbs water....
TRANSCRIPT
1
Kingdom Plantae
Plant Evolution: Aquatic Ancestor
•Group of green algae is the closest living species to a possible land plant ancestor
2
Algae & Land Plant Similarities
•Both contain chlorophylls a and b •Have chloroplasts •Store starch •Cellulose in cell walls
3
4
Terrestrial Habitat
Aquatic Habitat
Plant Adaptations to Land Problems:
1. Need minerals 2. Gravity 3. Increase in
Height for Light
4. Adaptations for Drier environment
5. Reproduction
Solutions: 1. Roots absorb H2O &
minerals 2. Cellulose in cell walls
are rigid 3. Vascular Transport
System 4. Waxy cuticle &
stomata with guard cells
5. Pollen containing sperm
5
Common Characteristics of Plants
•Multicellular •Autotrophic (photosynthesis) •Surrounded by cell walls containing cellulose •Stores reserve food (starch)
6
General Reproduction in Plants
•Alternation of generations life cycle •Diploid (2n) sporophyte stage •Haploid (1n) gametophyte stage •Produce multicellular embryo
7
8
2n Sporophyte
1n gametophyte
1n pollen
Ovary with 1n ovules (eggs)
2n seed with plant embryo
Sporophyte
Gametophyte
Taxonomy • Plants are divided into two groups
• Based on the presence or absence of an internal transport system known as the Vascular System
9
Vascular Bundles
Vascular System
•Xylem tissue carries water and minerals upward from the roots •Phloem tissue carries sugars made by photosynthesis from the leaves to where they will be stored or used
10
Nonvascular Plants
• Do not have vascular tissue for support or conduction of materials
• Called Bryophytes
• Require a constantly moist environment
11
Sporophyte stage
Gametophyte Stage
Nonvascular Plants
•Plants can’t grow tall •Cells must be in direct contact with moisture •Materials move by osmosis cell-to-cell •Sperm must swim to egg through water droplets
12
Nonvascular Plants examples
•mosses
• liverworts
•hornworts
13 Liverworts Hornworts
Moss
Main Parts of Vascular Plants
• Shoots -Attach leaves -Photosynthetic
part of plant • Roots
-Absorb water & minerals
-Anchors the plant
14
Vascular Plants
Subdivided into two groups –1.Seedless vascular plants 2.Seed-bearing vascular plants
15 Club Moss
Vascular Plant Taxonomy
copyright cmassengale 16
Seedless Vascular Plants • club moss
• horsetails
• whisk ferns
• ferns
17 Horsetails Whisk ferns
Ferns
Seed-Producing Vascular Plants •Includes two groups – Gymnosperms and Angiosperms •Gymnosperms have naked seeds in cones •Angiosperms have flowers that produce seeds to attract pollinators and produce seeds
18
Seed-Producing Vascular Plants Groups
• Gymnosperm –cone bearing or “naked seed”
• Angiosperm-flowering plants
19
Gymnosperms
•Examples: pine, cedar, spruce, and fir
•Cycads, ginkgo
20
Ginkgo
Cycad
Pine
Gymnosperms •Contains the oldest living plant – Bristle cone pine
•Contains the tallest living plant – Sequoia or redwood
21
Angiosperms
• Flowering plants (not all flowers can be seen!) • ~200,000 species; makes up 80% of all plant species on Earth
• Seeds are formed when an egg or ovule is fertilized by pollen in the ovary
• Requires pollination
• Self-pollination, wind pollination, animal influence pollination (35%)
• Fruits are frequently produced from the ripened ovaries of the flower…you might not be able to see all fruit!
22
Angiosperms
•Division Anthophyta •Subdivided into two classes – Monocots and Dicots •Monocots have a single seed cotyledon •Dicots have two seed cotyledons
23
Monocots
•Parallel venation in leaves •Flower parts in multiples of 3 •Vascular tissue scattered in cross section of stem
24
Dicots
•Net venation in leaves •Flower parts in multiples of 4 or 5 •Vascular tissue in rings in cross section of stem
25
Monocots Monocots
Dicots Dicots
How can you tell the difference?
Plant Kingdom
Non Vascular
seedless
Club moss
angiosperm
Douglas fir
monocot
Liverworts
moss
Flowers are in ______
_____ veins in leaves
______ veins in leaves
Flowers are in_____
Stop
copyright cmassengale 30
Seed Plant Structure
•The three principal organs of seed plants are roots, stems, and leaves. •These organs perform functions such as the transport of nutrients, protection, and make food.
Seed Plant Structure
Function of Roots:
•absorb water and
dissolved nutrients.
•anchor plants in
the ground.
Seed Plant Structure Stems provide:
•a support system for
the plant body.
•a transport system
that carries nutrients.
Seed Plant Structure Function of Leaves: •A plant’s main photosynthetic system.
Vascular Tissue
•Vascular tissue forms a transport system that moves water and nutrients throughout the plant. •Vascular tissue is made up of xylem, a water-conducting tissue, and phloem, a food-conducting tissue.
Meristematic Tissue •New cells are produced at the tips of the roots and stems.
This is the meristem tissue that is responsible for continuing growth throughout a plant's lifetime.
Types of Roots
• In some plants, the primary root grows long and thick. This primary root is called a taproot.
• A carrot is an example of a taproot.
Types of Roots
•Fibrous roots branch so that no single root grows larger than the rest.
•Fibrous roots are found in grasses.
Root Structure and Growth •The root’s surface is covered with root hairs. Root hairs increase the surface area for water to enter the plant.
Root
hairs
Root Structure and Growth
•The epidermis protects the root and also absorbs water.
Epidermis
Root Structure and Growth
•Inside the epidermis is a layer of ground tissue (cortex)
Ground
tissue
(cortex)
Root Structure and Growth
•The cortex extends to another layer of cells, the endodermis.
•The endodermis completely encloses the vascular cylinder.
Endodermis
Root Structure and Growth •The vascular cylinder is the central region of a root that includes the xylem and phloem.
Vascular cylinder
Phloem
Xylem
Root Functions
•Osmosis and active transport move water and minerals from the root epidermis into the cortex.
Stems
Stem Structure and Function
•Stems have three important functions: 1. they produce leaves,
branches and flowers 2. they hold leaves up to the
sunlight 3. they transport substances
between roots and leaves
•All seed plants undergo primary growth, which is an increase in length. •For the entire life of the plant, new cells are produced at the tips of roots and shoots. Year 1 Year 2 Year 3
Primary
growth
Apical meristem
Primary
growth
Leaf
scar
Secondary Growth of Stems
•Vascular cambium increases the thickness of stems over time.
•Cork cambium produces the outer covering of stems (AKA: bark) which also increases the thickness of the stem.
Secondary Growth of Stems
• The vascular cambium appears as a thin layer • xylem cells
move toward the center
• phloem cells move toward the outside and becomes part of the bark.
Leaves
Leaf Structure
•The structure of a leaf is optimized for absorbing light and carrying out photosynthesis. •6CO2 + 6H2O C6H12O6 + 602
Review Photosynthesis and Respiration
•How does the plant get the CO2? •How does the plant get the water? •Where does the glucose molecules go? •Where does the O2 molecules go?
Leaf Structure •Leaves are covered on the top and bottom by epidermis which is used for protection.
Upper
Epidermis
Lower
Epidermis
Leaf Structure •The epidermis of many leaves is covered by the cuticle which prevents drying out.
Cuticle
Leaf Structure
The
veins
of
a
leaf Xylem
Phloem Vein
Leaf Functions • Palisade mesophyll are closely-packed cells absorb light that enters the leaf.
Palisade
mesophyll
Leaf Functions • Spongy mesophyll is loose tissue with many air spaces between its cells. It traps light for photosynthesis.
Spongy
mesophyll
Leaf Functions
• Stomata are porelike openings in the underside of the leaf that allow carbon dioxide and oxygen to diffuse into and out of the leaf.
Stoma
Leaf Functions • Each stoma consists of two guard cells.
• Guard cells control the opening and closing of stomata by responding to changes in water pressure.
Guard cells
Leaf Functions
• Transpiration is the loss of water through its leaves. This lost water is replaced by water drawn into the leaf through xylem vessels in the vascular tissue.
Leaf Functions Plant leaves allow gas exchange between air spaces in the spongy mesophyll and the exterior by
opening their stomata.
Leaf Functions • Guard cells are specialized cells that control the stomata.
• Stomata open and close in response to changes in water pressure within guard cells.
Leaf Functions • When water pressure within guard cells is high, the stoma open.
Leaf Functions • When water pressure within guard cells decreases, the stoma closes.
Stop
65
66
Flower and Seed Plants
Gymnosperms & Angiosperms
Gymnosperm
• Gymno means “naked”; sperm means “seed”
• Cone-bearing plants
• Pines, Cedars, firs….coniferous Plants
• Sporophyte and gametophyte life stages
67
68
Gymnosperm Life Cycle
69
70
ANGIOSPERMS
•Angiosperm means “covered seed”
•Have flowers
• Live everywhere – dominant plants in the world
•Angiosperms are the most successful and advanced plants on earth
Angiosperm Plant Reproduction
•Asexual Reproduction- •No partner
•Sexual Reproduction- •Cross fertilization
71
Asexual reproduction • Plant can reproduce
asexually by: • Breaking plant parts off
• Roots (Runners, stolons, suckers, etc.)
• Bulbs
72
Angiosperm Sexual Reproduction • Fertilization is the process of the female and male gametes
combining
• Cross fertilization • 2 separate plants with both sets of reproductive parts or only one set
• Self-Fertilization • Single plant with both male and female reproductive parts
73
74
Life Cycle Of an Angiosperm
What is the reproductive structure ? Flowers!
Flower Anatomy
MALE = stamen
Anther filament
FEMALE = Carpal or pistil
Stigma style ovary
Flower Anatomy
76
77
Flower structure • Male sex organs: Stamen: composed of anther –
organ that produces pollen.
78
Flower structure
• Female sex organs: The carpel The Ovary is the enlarged base that contains the ovules
The stigma is
the sticky end
of the carpel
for the pollen
grains to
adhere
79
Flower structure
• Sepals (green) are the outermost whorl of leaf it protects the flower.
• Petals (usually colored) are the inner whorl of leaf it attracts a pollinator.
copyright cmassengale 80
Angiosperm Reproduction
Angiosperm Reproduction
copyright cmassengale 81
Types of flowers or inflorescence A flower is….
• Complete = has both female AND male reproductive parts
• Incomplete = has only female OR male reproductive parts
• Perfect = has both female AND male reproductive parts
• Imperfect = has only female OR male reproductive parts
• Pistillate flower is a flower with only female parts.
• Staminate flower is a flower with only male parts.
84
* Pollination = Pollen falls on a stigma
when wind, bees, or bats carry it. * Fertilization = sperm (pollen grain) & egg (ovule) join together in the flower’s ovary. - The zygote develops into the embryo part of the seed. - The ovary around the seed develops into a fruit.
85
86
Seeds • Cotyledon is stored food tissue – for the embryo to
grow
• Mature ovule becomes the seed coat and/or fruit
87
Seeds
• Seeds contain a young, developing plant embryo
• Seeds are covered with a protective seed coat Seeds form from ripened ovules after fertilization
88
Seed Structure Examples:
89
Seed Dispersal • Seeds must be scattered
(dispersed) away from the parent plant
• Testa (seed coats) may last thousands of years
• Seeds eaten by animals aren’t digested but pass out with wastes
90
Seed Dispersal
• Seeds may have adaptations such as stickers, hooks, or fuzz to adhere to animals
91
Seed Dispersal
•Both water and wind can scatter seeds
Wind Dispersal
Water Dispersal
92
Fruits • Fruits form when ovary with ovules ripen
• May be dry and hardened (nuts)
• May be enlarged and fleshy (berries, apples, tomatoes)
• Used to help disperse seeds
93
Types of Fruits
•Simple fruits – form from a single ovary (apple)
•Aggregate fruits – forms from several ovaries of the same flower (blackberry)
94
Tropism = a plant’s growth response toward or away from a stimulus. •Stimuli can be light, touch, and gravity. •Touch (thigmotropism): vines coil around anything they touch.
Geotropism or Gravitropism
• Gravity • roots grow toward soil
and stems grow away from gravitational pull
95
• Light (phototropism):
leaves, stems, grow toward light.
97
Hormones = a chemical that affects how
the plant grows and develops, and make tropism possible. * Hormones also control germination, formation of flowers, stems, and the shedding of leaves and ripening of fruit.
Hormones
• Gibberellins: stimulates the growth and the development of fruits and seeds. • Cytokinins: Stimulates the growth of cells
• Ethylene: a gas released from fruit that promotes
ripening.
Hormones
• Auxin stimulates cell elongation in a rapidly growing region near the tip of the plants root or stem.
• If light shines on one side of a stem, auxin moves to the shaded side and causes that side to grow faster so the stem bends
toward the light as it grows.
Plant Responses to Environmental Stimuli • a decrease in water pressure (or Turgor Pressure)
in plant cells causes wilting.
• Turgor Pressure is the water pressure in the large central vacuole pushing up against the cell wall. • Decreased turgor pressure = wilting
• Stable turgor pressure = stable plant or turgid
• Increased or excessive turgor pressure = cell breakage (doesn’t happen often due to osmosis and diffusion across the cell membrane!)
100